R. J. Gornall (1985) reviewed the nomenclature of Leptarrhena. Based on molecular data, D. E. Soltis et al. (1993) placed it and the Asian, monospecific Tanakaea Franchet & Savatier sister in a group also including Boykinia, Jepsonia, Sullivantia, and Telesonix. Anther dehiscence in Leptarrhena and Tanakaea, which is by broad, terminal openings as opposed to longitudinal slits, appears to be unique in Saxifragaceae (H. G. A. Engler 1930). Soltis (1984d) found the karyotype of Leptarrhena to be distinct within the family.